2 files changed, 23 insertions, 0 deletions
diff --git a/cmd/libsnap-confine-private/cgroup-support.c b/cmd/libsnap-confine-private/cgroup-support.c
index 03dc4b160f..c61d516a47 100644
--- a/cmd/libsnap-confine-private/cgroup-support.c
+++ b/cmd/libsnap-confine-private/cgroup-support.c
@@ -25,6 +25,7 @@
 #include <string.h>
 #include <sys/stat.h>
 #include <sys/types.h>
+#include <sys/vfs.h>
 #include <unistd.h>
 
 #include "cleanup-funcs.h"
@@ -66,3 +67,18 @@ void sc_cgroup_create_and_join(const char *parent, const char *name, pid_t pid)
 }
 debug("moved process %ld to cgroup hierarchy %s/%s", (long)pid, parent, name);
 }
+
+static const char *cgroup_dir = "/sys/fs/cgroup";
+// from statfs(2)
+static const int CGROUP2_SUPER_MAGIC = 0x63677270;
+
+bool sc_cgroup_is_v2() {
+ struct statfs buf;
+
+ int err = statfs(cgroup_dir, &buf);
+ if (err == 0 && buf.f_type == CGROUP2_SUPER_MAGIC) {
+ fprintf(stderr, "WARNING: cgroup v2 is not fully supported yet\n");
+ return true;
+ }
+ return false;
+}
diff --git a/cmd/libsnap-confine-private/cgroup-support.h b/cmd/libsnap-confine-private/cgroup-support.h
index 33e5ccc90b..f7f0ebaf9b 100644
--- a/cmd/libsnap-confine-private/cgroup-support.h
+++ b/cmd/libsnap-confine-private/cgroup-support.h
@@ -19,6 +19,7 @@
 #define SC_CGROUP_SUPPORT_H
 
 #include <fcntl.h>
+#include <stdbool.h>
 
 /**
 * sc_cgroup_create_and_join joins, perhaps creating, a cgroup hierarchy.
@@ -30,4 +31,10 @@
 **/
 void sc_cgroup_create_and_join(const char *parent, const char *name, pid_t pid);
 
+/**
+ * sc_cgroup_is_v2() returns true if running on cgroups v2
+ *
+ **/
+bool sc_cgroup_is_v2(void);
+
 #endif